1. Field of the Invention
The present invention relates to apparatus for drilling dowel holes or bores in a workpiece, injecting glue into the drilled dowel bores and then setting dowels into the bores. In particular, the present invention relates to improvements in such apparatus wherein a programable controller is provided for automatically controlling the movement of a combination drill head and dowel setting head along the length of the side edge of the workpiece. The programable controller is programmed to control operation of the combination drill head and dowel setting head, as the same is being moved along the length of the side edge of the workpiece, to (a) drill dowel bores at selected, spaced positions along the length of the side edge of the workpiece, (b) inject glue into the bores, and (c) set dowels in the glued bores.
2. State of the Art
Various types of apparatus have been proposed and used in the prior art for drilling bores or holes in a workpiece, injecting glue into the bores and then inserting or setting dowels into the glued bores. In the more simple apparatus as exemplified in U.S. Pat. Nos. 3,738,766 and 4,235,565, jigs are used for holding a power tool such as a portable drill. The workpiece is moved into position relative to the jig, and the portable drill is used to drill a bore into the workpiece. Additional bores can be formed by manually moving the workpiece to a new position. Once all the desired bores are formed, the workpiece is removed from the jig. Glue is then manually injected into the bores, and dowels are manually inserted into the glued bores.
In U.S. Pat. No. 4,693,647 a dowel hole drilling machine is disclosed having a work table and a jig containing a tool that drives a rotating drilling element. The workpiece is carried by the worktable, and the worktable moves toward the rotating drilling element when the workpiece has been located in proper position on the worktable. As the workpiece engages the rotating drilling element, a bore is drilled in the workpiece. After the workpiece has been removed from the table, glue can be injected into the bore and a dowel then set in the glued bore.
In U.S. Pat. Nos. 3,601,301 and 4,834,153 apparatus is disclosed in which the workpiece is held in place and multiple bores are formed in the workpiece simultaneously by multiple drilling elements which are moved as a unit towards the workpiece such that the drilling elements simultaneously engage the workpiece and drill bores therein. The drilling elements are then withdrawn and without moving the workpiece, multiple heads for injecting glue and inserting dowels are moved into alignment with the bores that were previously formed in the workpiece. These heads simultaneously inject glue into the respective bores and immediately thereafter insert dowels into the glued bores.
Apparatus for simultaneously forming a plurality of dowel bores in the side edge of a workpiece is known in the art. Such apparatus as shown in U.S. Pat. No. 4,639,171 comprises a work support upon which a workpiece can be securely held in proper position. A bank of drill chucks is provided, with the drill chucks being aligned and equally spaced relative to each other. The drill chucks are further driven by a common motor or drive unit. Drills are releasably attached to desired drill chucks to correspond with the number of bores that are to be formed in the side edge of the workpiece. The drills are attached to appropriate drill chucks so that proper spacing of the drills is achieved. The bank of drill chucks containing the selected drills moves as a unit toward the workpiece such that the drills simultaneously engage the edge of the workpiece and simultaneously drill bores in the edge of the workpiece. To vary the number of bores being formed in subsequent workpieces or the spacing of the bores, the drills must be removed and relocated to the appropriate drill chucks.
Although not shown in U.S. Pat. No. 4,639,171, apparatus in accordance with the previous paragraph is known in the art wherein a separate bank of dowel inserting devices are provided in addition to the bank of drill chucks. When the bank of drill chucks is withdrawn from the side edge of the workpiece in which the dowel holes have been formed, the bank of dowel inserting devices having individual dowel inserting members spaced at the same spacing as the dowel bores is brought into close proximity to the side edge of the workpiece, with the individual dowel inserting members being in alignment with the respective dowel bores in the side edge of the workpiece. The dowel inserting members have means for first injecting glue simultaneously into the dowel bores and then dowels are simultaneously inserted or set in the glued bores.
3. Objective
A principal objective of the invention is to provide a novel improvement in the dowel drilling and setting apparatus of the type used in forming a plurality of dowel bores in the side edge of a workpiece and which were referred to in the two immediately preceding paragraphs.